Holarctic is a big word that is used to describe an area on the Earth where many plants and animals live. Imagine a really big puzzle of the Earth's map. You might see that there are some places in the world where many animals and plants live, like in North America, Europe, and Asia. Scientists call this area the Holarctic region. It’s like a big neighborhood where many different creatures, like polar bears, wolves, and moose, live together. Even though they may look different and have different names in different parts of the world, they are all part of the same group that lives in the Holarctic. So, Holarctic is just a word that helps scientists describe a big area on Earth where many plants and animals live together.